Identification of Molecular Characteristics of Babesia spp. and Anaplasma marginale in Water Buffaloes: A Retrospective Study from Veracruz and Tabasco, Mexico

The main objective of the present study was to detect, with PCR assays and confirm by DNA sequencing of amplified target genes, the presence of Babesia and Anaplasma sp. in samples from infected water buffaloes in Veracruz and Tabasco, Mexico. Babesiosis, theileriosis and anaplasmosis are important tick-borne diseases of cattle worldwide including Kenya. Babesiosis and theileriosis are caused by the protozoan parasites, Babesia and Theileria respectively while anaplasmosis is caused by rickettsial organism known as Anaplasma. A cross-sectional study was conducted in 2017, using a non-probabilistic sampling method for convenience. The total population of water buffaloes from two production units (PU), located at the municipality of Sayula de Aleman, state of Veracruz, Mexico, were sampled for this study: Veracruz 1 (n = 61) and Veracruz 2 (n = 63). Similarly, the total population of water buffaloes from two production units (PU), in the municipality of Villahermosa, Tabasco state, Mexico, was sampled for this study: Tabasco 1 (n = 58) and Tabasco 2 (n = 51), for a grand total of 233 water buffalo samples. Specific genes encoding the B. bovis rhoptry-associated protein (RAP-1), the B. bigemina SpeI-AvaI restriction fragment, and the Anaplasma marginale major surface protein 5 (MSP5) were amplified using nested PCR assays. The identities of the hemoparasites were established by comparing the nucleotide sequences obtained in this study with those available in the GenBank database at the National Center for Biotechnology Information (NCBI) using DNA sequencing and BLASTn analysis for DNA homology hemoparasite identification. Water buffalo infection with at least one of the hemoparasites under study was detected in 45% (105/233) of the blood samples, while a mixed infection with B. bovis and B. bigemina was detected in 6.4% (15/233) of samples. For this cross-sectional study, mixed infections with the three hemoparasites were not detected. BLASTn analysis revealed that the nucleotide sequences of the water buffalo isolates shared sequence identity values ranging from 88 to 100% with previously published gene sequences of B. bovis, B. bigemina, and A. marginale. The findings of this study demonstrate that water buffalo are tick-borne hemoparasite carriers, just like cattle, and that they likely play a significant role in the epidemiology of bovine babesiosis in Mexico.